Pneumatic operating mechanism for doors, steps, or the like.



G. M. SPENCER.

PNEUMATIC GPERATQNG MECHANISM FOR DUO RS, STEPS, OR THE LIKE. APmcATmM mm IUNEB. 1909.

AA, EQfifi Patented Apr. 6, 1915.

i/Witnesses: v

WMx i 4 U ,M.

Aenlteetton filed June 25, 1%8.

To all whom it may concern:

Be it known that if, Gnonen M Sennonn,

a citizen of the United States, residing at St. Louis, in the State of Missouri, hays made a. certain new and usetul Invention in Pneumatic Operating Mechanism for iioors,

Steps,- or the like, of which the following is A further object is to provide means whereby the operating pressure is out oii before the end of-the stroke of the operating piston whereby the completion of the opera tion of the door or other device to be morerhis effected by the expansion of the pressure medium already supplied to the cylinder.

Other objects of the invention will appear more fully hereinafter.

The invention consists substantially in the construction, (iOlYllililfifilOfl, location and relative arrangement of parts all as will be more fully hereinafter set rorth, as shown inthc accompanying drawing and finally pointed out in the appended claims.

Referring to the accompanying drawing, and to the various views and reference signs a ppeai-ing thereon, Figure 1 is a. view in'eleration showing a pneumatic door operating mechanism embodying the principles of my invention. Figs. 2, 3 and l are diagrammatic views illustrating the valve action. Fig. 5 is a diagrammatic View illustrating the connections from the valve to the cylinder. Fig. is a View in side elevation of the "valve.

The same part is designated by the some reference sign wherever it occurs throughout the several views.

In the practical operation of pneumatic mechanism for opening and closing doors,

moving steps, or other devices, whereapres.

sure medium, such as compressed air, is admitted to a cylinder to operate a pistornit is a common practice to open one end of the cylinder to exhaust at the same time the other end is opened to admit the preshpemiiiestion oi Letters ZE-ietent.

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sure medium. Thereupon the dooror other device to be operated is started on its move-- merit as soon as the operating pressure 141-- niitted to the cylinder, or to one side of the operating piston is suiiicientiy in excess of the retarding pressure ordered by the escaping exhaust at the other of the cylinder, or on the other side of 1 piston, to develop the required power to overcome friction and the inertia of the door or other device to be operated. The door or other de vice then continues to move, provided item counters no obstruction, at e s eed depend end ti o .ent upon the rate of exhaust, or the difiter ence between the operating and exhausting pressures, until it reaches its final limit or movement. When. this final limit is at tained, the operating pressure remains an piied to one end of the cylinder or to. one side of the operating piston, and the other end of the cylinder or the other side of the. piston remains open to the exhaust, until. it is desired to operate the door or revise in the other direction when, through a Valve or other form of controller the, above operation is re 'ersed. It has been found by practical experience that in the operation of prion matic mechanism of'the character referred to, and especially in the operation of doors and steps or like devices, leakage cit-the. pressure medium occurs through the piston iackin and other 'oints which 'derelons decided objections. T his is especially true of the operationv of doors and steps on cars, for instance, since by farthe greater portion of the time the doors remain closed, and the constant application of the pressure medium to the operating piston while the door remains closed atiordsfan opportunity for leakageof the pressure medium, and Willie such leakage may be small, inv the aggregate of a days 0 erstion, for instance, it becomes a materia factor in the operation of the system. Again, Where pressure. in one end of the operating cylinder While-the door or other ,device remains in the limit of its movement, as, for instance, in its closed position, if a door, and it is desired to open the door, an appreciable interval of time must elapse before the door commences its opening movement to enable the pressure in the previously open end of the cylinder to overcome the exhausting iressure in the" previously closed end or the cylinder.

Again, in case the door or other device to its.

limit of its movement whereby the door. And in accordance 151011 I propose to employ in alinenient with cool be opernteclis forcibly cietainecl or helcl he- .tore its limit of movement is reached, the exhaust continues on one side' of the operating piston while the pressure on the other side continues to build on till it reaches the full tank or reservoi' 'ircssnre with the result that when the detaining obstruction is removed the cloor will move o its limit of movement with an object/lo; slam.

It is among the special objects and p poses oi my present invention overcome these and other (lifi'icul l the operation of appoint nature, and in. carrying out my i1 tion 1. propose to provide means whereby' when. the door or other device to he opcr l t the pressure medium is cqn eis hnustecl from, both ends r "i from both sides of 4, ems-ding "f ton also propose to provide no who operating medium is cut-oil h ill or other device to he operziitetl r I! A 1- w A sion 01 the snp ineo pressure inc: utilized in completing tlie'inov for ziccomplishing these Many specllicall and arrangements vention into therefore, have so. scribe, one constructio; esi're to be understood t in its broadest scope, 3 en claims not to be l mited. or re the exact constrn on and shown.

in the drawing reference notes the device to be open a, do"; B the arm A e the same; C, re power s casing in mhicl V valve or controlling the sup y and exl of operating i'neclinni to end from the cylinder. In the form shown. the cylinder is :1 double cylinder, or two cylinders arranged other, \vi h the pistons E, l respectiv'ely operating in said cylinders, and connected together by a rack G, the remote ends of the double cylinder eing closed and the proximate ends thereof being open to the atmosphere. he operating' arm B, is formed on or connected to i a segment gear 8 which meshes with one actuated. by the rgck G. This is pivoted asst 30 upon the standard H, formecl on the siclcs if tne pivot point 2. Acljnstahly mounted. on these ends, respectively, are the or blocks 3, 4-. Connected to the pivot pin of curved member 1, is no crank arm 5 having connection through rod 6, with a trip arm '2, whic A is connected to the valve in oasis; The relation the stop blocks r lugs 4*, with reference to the crank arm 9 such that when the operntlng nrni l suliiciently for in one direc- 0516i, the end of crank 111? one or the other of the s Jpas the case irny he, thereby rockand, through. the rock ".KHCIUL Lhcicot, operating the valve.

ng' ends oi toe crank arm 9 and ochs 8, l, are I i sl upctl that after am ha. ed :1 1 block =1 2 ed t 1, 1c @1213? continue i v t i 'Z'the the stop blocs. stop s nstnhly mounted on the roe (x sin; (I,

eesircd point in "he lie oi thr can then coinnue its movement any .ther valve move 4:, have shown (liaincler side or Working valve 31, the ports in the valve 2 6 being; indicated in clotted .t if. provided wi h grnnin at czilly the race of snp 'ily, and l The double tn the pistons li in s so as to the cyiincleiz is openeelto exhaust port 13.

But since the piston F at this time has uncov ere l port 15 t' ere is no pressure in the rignt nsno end the cylinder, sncl there- Iore ning oi the movement of the eonncetc I uois toward the right there no pressure i i-She right hand end of the cylinder l.

snopliecl th the has e ports 12-, or the cylinder conthe operating medium end 10; to

plished in the following manner:

observed that the valve 31, is provided with.

Through messes sequently the door begin'sto move instantly the valve is operated to the osition shown. in Fig. 2, and with a less egrce of 0 er- ,ating pressurethan would be require it 5 there was an opposing pressure in the right hand-of the cylinder. It is desirable, how ever, as the door continues ts movement, to

. build up an opposing pressure, or a resistance in the right hand end of the cylinlo der so as to prevent the door from slainrning, as well as to prevent accident or injury in case a erson or other obstruction should impede t e movement of, or be encouni'ered' by thcdoor. Thisis accom- It will be thereby confining whatever atmospheric air the right hand end of the cylinder may contain from the previously opened port 14:. This air can. escape, only through one of the restricted openings 16, 17, 18, ac

cording to theposition of the valve, and

thence through the exhaust port 13. The amount of this exhaust will, of course, be dependent upon the area of the small opening 16, 17 or 18, through which the exhaust is eficcted. The areas of these openings are calculated according to and depend largely upon the amount of pressurethat is being used, and upon the point at ivhichit is desired the cushioning should commencefthe weight and friction of the dooror other part to be moved, and other likecc. nditions, In actual practice, using the ordinary pressure of to 100 pounds comnionly employed in street car work it has been foundt5 that the opening 16, may be entirely dispensed with, as all the atmospheric air in the cylinder should be retained during the first part of the stroke of the piston in order that sufiicient back pressure may be built to up to properly cushion the operating pres sure during the latter part of the stroke. Toward the end of the stroke, however, the momentum of the door having been partially restrained by the building up cushion.

55 and the operating pressure being reduced by expansion, it is desirable that the back pressure or cushion pressure he also reduced, and this 1s accomplished by causing one or the other of the larger openings 17 or 18, 50 to be brought into register with the exhaust port 13. In case the operating or tank pressure is quite low, say 30 pounds, a small opening 16 is desirable, as otherwise the back pressure or cushion might build up 'tion of the door.

sulficiently to equal or exceed the operating pressure at a point too early in the opera- After the valve has been operated to the position shown in Fig. 2, the operationabove described is inaugurated and at a certain point in the operation thus I initiated, theposition of the valve is shifted automatically throughthe connections above described, into the position shown in Fig d, thereby cutting oil entirely the further supply of pressure to the left hand end of the cylinder through port 10. Thereat'ter the expansion. of the operating pressure prefiiouslysupplied to the left hand endof the cylinder is utilized to complete the movement of the door. The amount of operating pressure in the cylinder at the moment this cutoff takes place has no direct relation to the tank or reservoir pressure, as it is dependent solely onthe power required to move the door, the ports 10, 11 and 12, be ing inade,'in practice, sufliciently small to preventthe operating pressure to enter the cylinder too rapidly, and since there is-no exhaust pressure in' the opposite end of the cylinder to expel, the door will start to move the instant-the operating pressure is sufiicient to overcome the inertia, friction, etc.

The operating pressure in the. cylinder, therefore is governedsolely by the pressure required to IDQVQ/ the door and is not complicated ,by \the dhngth of time the door might linger beiore starting to move. This is a most desirable feature of my invention since in devices of this nature as heretofore "employed Where there is exhaustpressure to be taken into consideration, the length of timethe jdoor lingered before starting very greatly affects the operating 'pressurc. Ru-

fe'rring again'tojl ig. 3 it will be seen that not onlyis port cut oi? from the. pressure supply hut the exhaust port 13, communichtes with the cylindrical port 11, through the snuill hole'l'i, instead of hole 16, and hence thi'ough a hole of somewhat larger area to bonipensatc for the reduced expansioupressure' in the operating end of the cylinder; When the operating piston reaches the limit ot'its mdvement toward the right, the piston E uncovers the port ll, thereby opening the left hand end oi the cylinder to exhaust, and hence not only equalizing the pressure at both ends of the cylinder, or on both sides of the piston, but also avoiding the opportunity of leakage of prespiston packings, or other joints thereof.

When it is desired to actuate the operating ,pisto'n' toward the left the valve is shifted into the position indicated in Fig. 3, thereby repeating, 1n the apparatus the operation above described except that now the operating or tank pressure is supplied to they right hand end of the cylinder, while the of "l.

compression or cushioning elfect is secured in the left hand end,

T he valve may be initially operated in any suitable manner and by any suitable arrangement of connections, and from any convenient point- I have shown a control handle J, connected through intermediate devices K, for this purpose.

From the foregoing description it Will be seen that I avoid leakage of the pressure medium. It will also be seen that the cylinder is exhausted of operating medium at both ends when the door is at rest. By reason of this feature it follows that by operating the control handle to its extreme position in either direction the door is moved by power mechanisn'i, in the one direction to be opened and in the other direction to be closed, and when such control handle is -moved to centered or half Way position the power medium, is shut ofl', both ends of the cylinder is opened to exhaust, and thereafter the door may be moved by hand to any position. This is a desirable feature especially in the case of the use ofmy invention in connection with the doors of elevated, surface, subway or street or other cars, Where large crowds are handled as thereby I avoid the necessity of forcing, by powermechanism, the doors shut through a crowd of passengers who are only partially inside the door. In this case the control handle is placed in central position and'the door may then be closed by hand. It Will also be seen that the door begins to move instantly upon applying the operating pressure, and that l utilize the expansion of the operating" medium, after the supply thereof is out all", to complete the operation of the door other device to operated. ing now set forth theobject and naturc my invention and a construction embodying the principles thereof, What ll claim as new and useful and of my own invention and desire to secure by Letters Patent is:

1. The combination with a device to be moved, of pressure actuated operating means therefor, including a cylinder and pis ton, a valve for controlling the supply and exhaust of pressure medium to both ends of the cylinder, and operating when in centered position to open both ends of-the cylinder to exhaust, and means foircentering the valve as the device to be moved attains the limit of its movement.

2. lhe combination. with adevice to be moved, of pressure actuated operating means therefor, including a cylinder and piston, a valve to control the supply and exhaust of operating medium to and from the cylinder, and operating, When-in centered position, to open both ends of the cylinder to exhaust, and automatically operated means for centering the valve as the device 7 be moved attains the limit of its movement,

4. The combination with a device to be moved, of an operating cylinder and piston, the pressure on both sides of the piston being equalized when said device attains the limit of its movement, manually open ated means for admitting the pressure to one side of the piston and means for restricting the exhaust from the opposite side of the piston, means for cutting off the supply on the pressure side of the piston ant s matically before the device to be moved tains the limit of its movement and means for coincidently enlarging the area of the exhaust on the other side of the piston.

5. The combination with a device to be moved, off a double cylinder, connecting pistons operating therein, connections operated by the pistons for moving said device, and automatically operated means for simultaneously exhausting the pressures on opposite faces of the piston at the limit of their stroke. 7

6. The combination with a device to be moved, of cylinders arranged in alinement with each other, connected pistons respectively operating; in said cylinders, means operated by said pistons for moving said device, manually operated devices for controlling the supply and exhaust of pressure medium to and from the remote ends of said cylinders and atmospheric exhaust openings at the proximate ends of said cylinders, said exhaust openings being ufd covered by said pistons respectively as the reach the limits of their out stroke 7. lhe combination with a device to be moved of cylinders arranged in alinement with each other, connected pistons respectively operating in said cylinders, means operated by said pistonsfor moving said device, said cylinders being opened to the atmosphere at their proximate end and closed at their remote end, means manually operated for c ontrolling the supply and exhaust of operating medium to and from the remote ends of said cylinders, and exhaust port formed in said cylinders adjacent their proximate ends, said exhaust ports being controlled by the pistons.

'8. The combination with a device to be moved, of a cylinder and piston, a rack operated thereby, a pivoted segment gear operated by the piston and connected to said device for operating the same, a stand ported, a rocking membiaz carrmii lily map by said standard and having adjustabls stops, a Valve mechanism, connections making Inemben and mlw m eachemism 9.116;

means eperated by the gear to engage said stops,

in testlmony 'whsreuf i hava hareunta s93:

my in tha presence 01 the subscribing Wnfinesses, on thls first day of June, A. 1)., 10 1909.

GEORGE M. SPENCER;

Wiinasses S. E. DARBY, C. HUNICKE. 

